1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to a mechanism for efficient power control for a tune away mode in a DSDS device.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
Additionally, some wireless devices are configured to facilitate communication on two separate networks via two separate subscriptions. For instance, dual-subscriber identity module (SIM), dual standby (DSDS) devices may include two SIM cards—one card for a first subscription and a second card for a second subscription. Furthermore, each subscription may be associated with one or more technology types. For example, a first subscription may exclusively support 2 G communication technology, such as Global System for Mobile Communications (GSM), while the second subscription may support one or more 3 G communication technologies (e.g. Wideband Code Division Multiple Access (WCDMA)) and 2 G communication technology.
In DSDS devices, a user may establish a call, such as a voice call, data call, data session, text messaging session, or any other data transfer session, via one of the two subscriptions. Because most DSDS devices contain a single radio resource, such as a transceiver, where a first subscription has established an ongoing call with a first subscription network, a user equipment (UE) must tune the transceiver away to the second subscription at regular intervals to receive necessary paging signals and to transmit, for example, message acknowledgement signals and/or measurement indication signals. Therefore, while the first subscription continues an ongoing call, the transceiver may periodically tune away from the first subscription to the second subscription to receive such necessary paging and/or control information.
In some situations, power control (transmit power) poses a significant design problem in DSDS devices. Prior to tune away, the UE transmits at a certain transmit power. After the tune away is completed, the UE may have changed positions relative to the base station and the prior transmit power may no longer be suitable.
Therefore, improvements in the power control for tune away mode of DSDS devices are desired.